Non-equivalence of canine tissue and intraluminal PCO2 responses at different sites during hemorrhage and during resuscitation


Address correspondence and reprint requests to:
Dr. Piper Wall, Surgery Education Department, Iowa Methodist Medical Center, 1415 Woodland Ave., Suite 140, Des Moines, IA 50309.


Objective: The purpose of this study was to measure and compare the hemorrhage and resuscitation partial pressure of CO2 (PCO2) responses at a variety of sites, predominantly intraluminal gastrointestinal, in the same dog and among different dogs.

Design: Observational study.

Setting: Association for Assessment and Accreditation of Laboratory Animal Care accredited research laboratory.

Animals: Pound source mongrel dogs being used in 4 separate hemorrhage and resuscitation studies, the objectives of which were unaffected by the PCO2 monitoring.

Interventions: Fiber-optic PCO2 monitoring systems were used to simultaneously monitor subcutaneous (n=8), sublingual (n=8) PCO2, and intraluminal esophageal (n=10), gastric (n=27), duodenal (n=16), jejunal (n=8), and ileal (n=7) PCO2 of 28 dogs used in 4 hemorrhage and resuscitation studies.

Measurements and main results: The tissue or intraluminal PCO2 at all sites increased in response to hemorrhage. The rate and magnitude of esophageal, gastric, duodenal, jejeunal, and ileal intraluminal PCO2 varied widely between dogs for the same site and between sites in the same dog. Different gastrointestinal sites also responded differently to resuscitation. The rate and magnitude of changes in subcutaneous and sublingual PCO2 values were lower than those in the other tissues examined. The mean and maximum coefficients of variation for each site were as follows: subcutaneous 9%, 31%; sublingual 10%, 23%; esophageal 15%, 40%; gastric 26%, 90%; duodenal 25%, 70%; jejunal 25%, 95%; and ileal 34%, 87%.

Conclusions: At different tissue sites, PCO2 values do not respond equivalently to either hemorrhage or resuscitation. One site cannot, therefore, be reliably used to indicate the energy status of an alternate site.